The present invention relates to an apparatus for mechanically decoupling the resonator means of a gas dynamic laser from the other components of said gas dynamic laser, especially a high power gas dynamic laser. The resonator means extend at both sides through the structural components carrying the laser medium, whereby the zones through which the resonator means penetrate into the laser medium carrying components are elastically sealed in a vacuum tight manner. Further, the resonator means are connected through spring and damping elements with a supporting structure such as a floor.
An effective mechanical decoupling between the resonator means and the remaining components of a laser is of controlling importance especially in high power lasers. When dimensioning the resonator of such lasers it is namely necessary to take two essential considerations into account:
first, one must consider the high noise level as compared to other lasers due to the high flow speeds and the large body noise resulting therefrom in a gas dynamic laser; and PA0 second, the large cross-dimensions of the resonator mirrors relative to the mirror spacing must also be taken into account for these resonators having a high Fresnel-number. PA0 (a) an extraordinarily rigid structure for securing the resonator mirror to reduce the mirror vibrations to a minimum; and PA0 (b) an effective mechanical decoupling of the resonator structural components from the remaining members of the laser which decoupling must prevent the transmission of body noise to the resonator.
Both of the just mentioned features require:
In this type of laser the resonator mirrors are normally located immediately opposite the laser medium. Therefore, it is necessary that the structure carrying the mirrors penetrates at one or several points through the structure guiding the laser medium. Thus, a mechanical decoupling of the resonator from the remaining laser components requires a vacuum tight, elastic construction of the penetration zones so that the resonator may oscillate with a certain degree of motion freedom relative to a normal position due to the elastic coupling between the resonator and the remaining laser components. The resulting oscillations are damped in a suitable manner.
Prior art devices relevant to this particular type of laser structure have the disadvantage that the construction of the resonator frame carrying the mirror could not be made rugged enough because the elastic coupling and sealing used in the prior art did not permit a resonator mirror support structure having a large cross section. Please see in this respect especially U.S. Pat. No. 3,858,122.
A further disadvantage of prior art devices is seen in that the elastical coupling elements between the resonator and the remaining components of the laser are not arranged symmetrically relative to the resonator axis. Such elastic coupling elements cause the restoring force between the resonator and the remaining components. Thus, the resulting restoring forces are not exactly effective toward the normal position of the resonator axis. As a result, during the operation complicated superimposed or heterodyning oscillations are encountered instead of the simple normal oscillations of the resonator relative to the remaining laser components. In connection with such superimposed oscillations, however, the mean or average deviation of the resonator axis from the normal position is larger than in connection with normal oscillations. Such large mean deviation is a disadvantage for the power and optical quality of the decoupled laser beams due to the large mean misadjustments of the resonator relative to the flow channel and thus relative to the laser medium.